The invention relates to a test head having a device for making contact with test points of an electric component under test, which points are preferably arranged closely one next to the other.
Test heads of this type are used to make contact simultaneously with a plurality of test points, that are arranged one next to the other, of an electric component under test, for example, a semiconductor component. The test head comprises a plurality of pin-shaped contact elements which are comprised of an elastic material and, during a test procedure, they are brought to bear against one assigned test point in each case. The contact elements are part of a device for making contact, referred to below for convenience as a contactor assembly. The contact force is applied by folding out and/or bending the contact elements perpendicularly to their longitudinal extent under spring extension when the contact elements are placed on the test points or the test points are placed on the contact elements, respectively. The contact elements are arranged in feed-through openings of two guide panels which are spaced apart from one another. Owing to their function, the contact elements must be axially movably mounted in the feed-through openings of the guide panels. To prevent the contact elements in the ready-to-operate position of the test head, for example between two test procedures, dropping out of the feed-through openings under the influence of gravity, DE 23 64 786 discloses providing in the end region of a contact element a support head whose external dimensions are greater than the clear width of the feed-through openings. A counter-bearing which covers the feed-through openings is provided on the side of the upper guide panel facing away from the test specimen. The counter-bearing prevents the contact elements dropping out of the feed-through openings when the test head is turned around. The counter-bearing is non-detachably connected to the contactor assembly. As a result, the contact elements can be changed only with a large degree of expenditure, if at all, since, to do this, the counter-bearing has to be removed from the contactor assembly and the attachment means which hold the two parts together have to be destroyed. The relatively large distance between contact elements makes it no longer possible to make contact with small test points which are arranged in a very tight space, which is frequently the case, for example, with semiconductor components under test.